N-halamine composition for the prevention and elimination of odors

ABSTRACT

Articles can be provided with odor resistance by applying a dispersion of a halogenated heterocyclic N-halamine in an inert liquid carrier onto the surface of the article and allowing the inert liquid carrier to penetrate into it. The N-halamine accordingly becomes deposited on the surface of the article after the inert liquid carrier penetrates into the article. This method can be used to provide odor resistance to a variety of substrates, including garbage bags. It can also be used to deposit other functional particulates onto the surface of substrates having sufficient porosity to take up the vehicle. For instance, such functional particles can be oxidants that display antimicrobial and/or enzyme inhibitory efficacy or particles having toxin interaction potentials through oxidative degradation or adsorption of toxic substances in air and/or water, such as fluoride uptake by metal oxide microparticles.

This is a divisional application of U.S. patent application Ser. No.15/872,617, filed on Jan. 16, 2018 (now issued as U.S. Pat. No.10,512,705), which claims the benefit of U.S. Provisional PatentApplication Ser. No. 62/447,187, filed on Jan. 17, 2017. The teachingsof U.S. patent application Ser. No. 15/872,617 and U.S. ProvisionalPatent Application Ser. No. 62/447,187 are incorporated herein byreference in their entirety.

TECHNICAL FIELD OF THE INVENTION

The present invention relates to compositions that can be used toprevent and eliminate odors which are emitted from solid articles andaqueous media. It also provides methods for utilizing such compositionsin specific applications. In one embodiment of this invention novelcompositions are used remove contaminants, including toxic materials,from aqueous media or air. In another embodiment the novel compositionsare used to inhibit enzymes. In another embodiment the novelcompositions are used to inactivate microbes.

BACKGROUND OF THE INVENTION

It is desirable to eliminate or at least to control odors that resultfrom various activities and/or which are associated with certain objectsand places. For instance, the repugnant odor that is sometimesexperienced in public restrooms can be almost overwhelming. Portabletoilets also commonly emit malodors. Garbage cans, dumpsters, trashbags, dirty clothes hampers, and a wide variety of other articles usedin homes, commercial settings and industry can also be the source ofunpleasant odors.

Frequent and thorough cleaning is an age-old and generally effective wayto control odors in many settings. The methodical cleaning of an articleremoves or destroys odor-causing bacteria and other materials that canbe the source of odors. Over the years, excellent cleaning products anddisinfectants, including soaps and detergents containing antimicrobialagents, have been developed. However, in some cases cleaning is not aneffective or practical means for odor control.

In addition to cleaning products there are numerous commerciallyavailable compositions which can be used to control or reduce the levelof various odors. These odor management compositions can be divided intothree categories which are based on their functionality. Thesecategories of odor management compositions are defined as odor maskingcompositions (which masks odors through the use of fragrances orperfumes), deodorizing/sanitizing compositions, which bind to odors oreliminate the microorganisms that are responsible for the production ofsaid odors, and combination odor masking and deodorizing/sanitizingcompositions (which bind to odors and eliminate the microorganismsresponsible for the production of said odors, as well as introducing aperfume or fragrance). Odor masking compositions primarily function byproviding a large quantity of a perfume or fragrance that overwhelms thesenses, masking odors without removing or modifying the source of saidodor. Deodorizing/sanitizing compositions function by containing activeagents that function in a deodorizing and antimicrobial capacity. Thedeodorizing agents chemically bind to existing odors deactivating them,while the antimicrobial agents are responsible for eliminating themicroorganisms responsible for the production of said odors. Combinationodor masking and deodorizing/sanitizing compositions are provided withboth a deodorizing/sanitizing agent and an odor masking composition thateliminates the source of a particular odor while providing an additionalfragrance or perfume to the area of application. Of these odormanagement compositions, deodorizing/sanitizing compositions are ofparticular interest due to their various applications and incorporationinto new and existing odor management systems.

Current deodorizing/sanitizing compositions can be formulated using aplurality of active deodorizing/sanitizing agents. One of these activesanitizing agents includes sodium tetraborate decahydrate, commonlyknown as “borax.” Borax is a boron salt that has the chemical formulaNa₂[B₄O₅(OH)₄].8H₂O in solution. Borax is able to function as adeodorizing/sanitizing agent as a result of its co-complexing abilitythat enables it to stably bind with various substances forming complexions. The ability to form complex ions enables borax to function as adeodorizing agent but additionally grants it antimicrobial properties.These antimicrobial properties are a result of the borax formed complexions inhibiting key metabolic pathways of several microorganisms.

Another active deodorizing/sanitizing agent is colloidal silver.Colloidal silver is metallic silver nanoparticles formed afterionization of silver or as a result of a chemical reaction whichsynthesize zero valent silver from mono valent silver cations. The zerovalent silver cations that are formed, disperse in a colloidalsuspension, wherein the colloidal suspension provides the silvernanoparticles separated between 10 nanometers (nm) to 100 nanometers(nm) apart from another silver nanoparticle. Through this uniquearrangement, silver nanoparticles have unique optical, electrical andthermal properties, in part due to significant surface area to volumeratio. The colloidal dispersal of the silver nanoparticles grants asolution with silver nanoparticles with deodorizing and antimicrobialproperties. The deodorizing properties are provided by the ability ofthe silver nanoparticles to react with substances more frequently due tothe surface area to volume ratio. The antimicrobial properties areprovided by the ability of the silver nanoparticles to inhibit aerobicmetabolism in various microorganisms.

U.S. Pat. No. 9,392,784 provides an odor management composition and amethod for creating said odor management composition containing theactive deodorizing and antimicrobial agents of silver nanoparticles in acolloidal suspension, commonly known as colloidal silver, and sodiumtetraborate decahydrate, commonly known as borax. The method of U.S.Pat. No. 9,392,784 creates a combination colloidal silver borax solutionthrough an in situ reaction that occurs at standard temperature andpressure values, between a formulated borax solution and a formulatedsilver nanoparticle source solution. The resulting colloidal silverborax solution results in a deodorizing and antimicrobial solution thateliminates various odors and reduces microbial presence responsible forthe production of said odors. Additionally, the colloidal silver boraxsolution is reported to have long-term shelf stability.

U.S. Pat. No. 9,392,784 more specifically reveals an odor eliminatingsolution comprises the active deodorizing and antimicrobial agents ofsilver nanoparticles dispersed in colloidal suspension in a solutioncontaining excess sodium tetraborate decahydrate, commonly referred toas borax. The silver nanoparticles provide deodorizing and antimicrobialproperties through the colloidal dispersion which provides a highsurface area to volume ratio for the suspension. The sodium tetraboratedecahydrate provides deodorizing and antimicrobial properties throughits co-complexing ability with various substances. The combination ofboth is reported to provide long term stability as well as deodorizingand antimicrobial activity.

The problem associated with water which is contaminated with harmfulmaterials is a serious problem which is of growing concern. Forinstance, water supplies can easily become contaminated with toxiccompounds from industrial, commercial, mining, and agricultural sources.More specifically, in the world today water supplies from lakes, rivers,and underground sources are frequently contaminated with phosphates,chromates, arsenates, and a wide variety of dangerous organic compounds.In other cases, it is important to be capable of effectively removingtoxic compounds which are intentionally introduced into bodies of wateror the air by terrorist groups or in warfare. For example, the abilityto effectively remove gases used in warfare, such as mustard gas ornerve gas, from air is of critical importance.

A technique for the purification of contaminated water is described in“Surface Engineered Zeolite: An Active Interface for Rapid AdsorptionandDegradation of Toxic Contaminants in Water” by Ruchi Shaw, Richa Sharma,Sangeeta Tiwari, and Sandeep Kumar Tiwari, ACS Appl. Mater. Interfaces2016, 8, 12520-12527. In this method zeolite is surface modified to formnovel multifunctional materials having capability for simultaneous andfacile removal of heavy metals [Pb(II)], organic pollutants [methyleneblue dye], and microorganisms [E. Coli, S. Aureus, and Pseudomonas] fromcontaminated water. The procedure involves formation of core-shellparticles with a functional core of zeolite and a porous shell of ZnOnanoflakes which not only imparts photocatalytic and antibacterialproperties but also renders the surface negatively charged, therebyfacilitating rapid adsorption of Pb(II) and methylene blue dye. However,the procedure described in this publication is of questionablecommercial applicability.

Free standing and strong odor-removing composite films of cellulosenanofibrils (CNF) with a high content of nanoporous zeolite adsorbentsmade by being colloidally processed are described in“Nanocellulose-Zeolite Composite Films for Odor Elimination” by NedaKeshavarzi, Farshid Mashayekhy Rad, Amber Mace, Farhan Ansari, FaridAkhtar, Ulrika Nilsson, Lars Berglund, and Lennart Bergstro, ACS Appl.Mater. Interfaces 2015, 7, 14254-14262. In this publication it isreported that thermogravimetric desorption analysis and infraredspectroscopy combined with computational simulations showed thatcommercially available silicalite-1 and ZSM-5 have a high affinity anduptake of volatile odors like ethanethiol and propanethiol. It isfurther reported that these materials are also effective in the presenceof water.

SUMMARY OF THE INVENTION

This invention reveals a method of manufacturing an odor resistantarticle which comprises applying a dispersion of a halogenatedheterocyclic N-halamine in an inert liquid carrier to the surface of thearticle and allowing the inert liquid carrier to penetrate into thearticle, wherein the inert liquid carrier does not react with halogenatoms in the halogenated heterocyclic N-halamine, and wherein thehalogenated heterocyclic N-halamine becomes deposited on the surface ofthe article after the inert liquid carrier penetrates into the article.This method can be used to provide a high level of odor resistance to awide variety of substrates. It is of particular value for use inmanufacturing garbage bags having a high level of odor resistance. Insome embodiments of this invention odor control is achieved byantimicrobial activity and/or enzyme inhibition.

In another embodiment of this invention toxins and other undesirablematerials can be removed from water or air by means of chemicaldegradation/oxidation or high affinity adsorption. This is typicallyaccomplished by depositing the desired active material onto a suitablefilter through which the water or air flow being treated passes. Thetoxin is normally removed from the water or air stream by adsorption,chemical degradation, or oxidation. In any case, the methodology of thisinvention is used for the detoxification of water or air to make it moresuitable for coming into contact with humans or animals.

One embodiment of this invention more specifically relates to method ofmanufacturing an odor resistant plastic film which comprises applying adispersion of a halogenated heterocyclic N-halamine in an inert liquidcarrier to the surface of the thermoplastic film and allowing the inertliquid carrier to penetrate into the plastic film, wherein the inertliquid carrier does not react with halogen atoms in the halogenatedheterocyclic N-halamine. In one specific embodiment of this inventionthe plastic film is in the form of a garbage bag, trash bag, or bin bag.Trash bags are normally made from polyethylene because it is tough,puncture resistant, light, and flexible. Due to its relatively low costlow density polyethylene is typically used. However, in applicationswere higher strength bags are needed high density or linear low densitypolyethylene can also be utilized.

In manufacturing garbage bags molten polyethylene is extruded, typicallyat a temperature which is within the range of 365° F. to 465° F.,through a die into a ring. The ring is then blown into a bubble andcooled to below its melting point into a long tube. Then, rollers areused to collapse the bubble into a flat tube. The flat tube is then cutto the desired length and heat-sealed on one end with the other endremaining open. Next, the trash bags are then folded, stacked, andinserted into their packaging for use by a consumer. Such bags are maketo be odor resistant in accordance with this invention by applying,typically spraying, a dispersion of a halogenated heterocyclicN-halamine in an inert liquid carrier onto the surface of the inside oroutside of the bag and then allowing the inert liquid carrier topenetrate into the walls of the bag leaving particles of the halogenatedheterocyclic N-halamine walls of the bag. The walls of such trash bagsare normally 0.0002 inch to 0.005 inch thick.

This invention accordingly relates to a garbage bag having walls whichare comprised of polyethylene, wherein said walls of the garbage bag arecoated with particles of a halogenated heterocyclic N-halamine having aparticle size which is within the range of about 0.01 μm to 20 μm, andwherein the particles of the halogenated heterocyclic N-halamine arepresent only of the surface of the walls of the garbage bag.

In another embodiment of this invention relates to a method formanufacturing a medium for purifying fluids which comprises applying adispersion of a micronized metal oxide in an inert liquid carrier to thesurface of a substrate having a high surface area and allowing the inertliquid carrier to penetrate into the substrate leaving the micronizedmetal oxide stranded on the surface of the substrate. The micronizedmetal oxide utilized in this embodiment of the invention will typicallyhave a high affinity for sequestering contaminants, such as toxicmetals.

This invention also provides a method for manufacturing a medium forpurifying fluids containing toxic compounds which comprises applying adispersion of a halogenated heterocyclic N-halamine in an inert liquidcarrier to the surface of a substrate having a high surface area andallowing the inert liquid carrier to penetrate into the substrate,wherein the inert liquid carrier does not react with halogen atoms inthe halogenated heterocyclic N-halamine, wherein the halogenatedheterocyclic N-halamine is capable of destroying the toxic compound byoxidative action, and wherein the halogenated heterocyclic N-halaminebecomes deposited on the surface of the substrate after the inert liquidcarrier penetrates into the substrate. This medium can be beneficiallyemployed in removing toxic gases from the air and other gases. Forinstance, it can be used in purifying air that has been contaminatedwith nerve gas, mustard gas and other gases used in chemical warfare.

The subject invention also provides a deodorizing solution which iscomprised of an organic liquid and a halogenated heterocyclicN-halamine, wherein the organic liquid does not react with halogen atomsin the halogenated heterocyclic N-halamine, and wherein the halogenatedheterocyclic N-halamine is soluble with the organic liquid. Thisdeodorizing solution is of great value in deodorizing toilets andurinals.

Air filters can be made in accordance with this invention by treatingconventional air filtration media with a dispersion of a halogenatedheterocyclic N-halamine in an inert liquid carrier. Such air filters arehighly efficient with respect to removing a wide variety of organiccontaminants from air streams. In a preferred embodiment of thisinvention conventional HEPA (high-efficiency particulate arrestance)filters can be treated with the liquid dispersion of this invention toproduce filters that are highly efficient at removing both particulatematter and organic compounds from air streams. It should be noted thatconventional HEPA filters must be capable of removing at least 99.97% ofparticles having a size of 0.3 μm. In any case, such filters can bebeneficially used in commercial, industrial, and residential settings,such as hospitals, clinics, offices, stores, factories, warehouses,chemical plants, apartment buildings, and homes. The air filters of thisinvention can be incorporated into the central heating/cooling system ofbuildings, exhaust systems, intake systems, or as stand-alone roomfilters. They can also be used in automobile and aircraft cabin filters.

A number of states now allow for the use of marijuana for medical and insome cases recreational purposes. This has created a demand for airfilters that can effectively remove odors associated with the productionand burning of marijuana from greenhouses where it is grown, from theexhaust gases emitted from such greenhouses, and from buildings wheremarijuana is ultimately used. Air filtration media which has beentreated with a dispersion of a halogenated heterocyclic N-halamine in aninert liquid carrier is highly useful for these purposes.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a SEM image of a zeolite substrate which has been coated with5 micron particles in accordance with this invention as described inExample 1.

FIG. 2 is an EDS line scan of a zeolite substrate which has been coatedwith 5 micron particles in accordance with this invention as describedin Example 1.

FIG. 3 is a bar graph showing immediate (5 minute) headspace ammoniacontent after daily litter applications of ammonia equivalent to anaminal's urine deposits, assuming all the urinary urea is microbiallyconverted to ammonia each day as described in Example 14.

FIG. 4 is a bar graph showing immediate (1 min) headspace content afterapplying a H₂S solution into the water as described in detail in Example17.

DETAILED DESCRIPTION OF THE INVENTION

While the making and using of various embodiments of the presentinvention are discussed in detail below, it should be appreciated thatthe present invention provides many applicable inventive concepts thatcan be embodied in a wide variety of specific contexts. The specificembodiments discussed herein are merely illustrative of specific ways tomake and use the invention and do not limit the scope of the inventiondescribed herein.

To facilitate the understanding of this invention, a number of terms aredefined below. Terms defined herein have meanings as commonly understoodby a person of ordinary skill in the areas relevant to the presentinvention. Terms such as “a”, “an” and “the” are not intended to referto only a singular entity, but include the general class of which aspecific example may be used for illustration. The terminology herein isused to describe specific embodiments of the invention, but their usagedoes not limit the invention, except as delineated in the claims hereof.

Halogenated heterocyclic N-halamines are utilized in several embodimentsof this invention. It is typically preferred for the halogenatedheterocyclic N-halamine to be a partially halogenated hydantoin. Thesepartially halogenated hydantoins are generally of the structuralformula:

where X₁ and X₂ independently represent hydrogen atoms or halogen atomsand R₁ and R₂ independently represent linear or branched alkyl groupscontaining from 1 to about 10 carbon atoms. It is normally preferred forR₁ and R₂ represent an alkyl group containing from 1 to 4 carbon atoms.It is also normally preferred for the halogen atoms in the partiallyhalogenated hydantoins to be chlorine atoms or bromine atoms. Somerepresentative examples of partially halogenated hydantoins that can beemployed in the practice of this invention include Cl_(0.5-5,5)-dimethylhydantoin, Cl_(0.9-5,5)-dimethyl hydantoin, Cl_(1.1-5,5)-dimethylhydantoin, Cl_(1.05-1.4-5,5)-dimethyl hydantoin, monochloro-5,5-dimethylhydantoin (MCDMH), Br_(0.9-5,5)-dimethyl hydantoin,monobromo-5,5-dimethyl hydantoin (MBDMH), Cl_(0.5-5)-methyl-5-ethylhydantoin, Cl_(0.9-5)-methyl-5-eth-yl hydantoin,Cl_(1.1-5)-methyl-5-ethyl hydantoin, Cl_(1.05-1.4-5)-methyl-5-ethylhydantoin, monochloro-5-methyl-5-ethyl hydantoin,Br_(0.9-5)-methyl-5-ethyl hydantoin, and monobromo-5-methyl-5-ethylhydantoin. Some preferred partially halogenated hydantoins includeCl_(0.9-5,5)-dimethyl hydantoin, Cl_(0.9-5)-methyl-5-ethyl hydantoin,Cl_(1.1-5,5)-dimethyl hydantoin, and Cl_(1.1-5)-methyl-5-ethylhydantoin. Monochloro-5,5-dimethyl hydantoin is the highly preferredpartially halogenated hydantoin for utilization in the practice of thisinvention.

Some representative examples of additional halogenated heterocyclicN-halamines that can be used in the practice of this invention includeN-chloro-N-sodiomethylbenzenesulfonamidate trihydrate,N,N-dichloro-4-methylbenzenesulfonamide,N-bromo-N-sodio-4-nitrobenzenesulfonamidate,N,N-dichlorobenzenesulfonamide, N-chloro-N-sodiobenzenesulfonamidate,mono-chlorosulfamate, dichlorosulfamate, N-chloroimidodisulfonates,sodium N-chloro-N-arylsulfamates,2,4,6,8-tetrachloro-2,4,6,8-tetrazobicyclooctane-3,7-dione, sodiumtrichloroimidometaphosphamate, N-halosulfinylamines,N-halo-N-sodioamidates, chloroisocyanurates, N-halocarbamidates,N-halosulfonamidates, N-chloro-imidodisulfonate,N,N-dichloromethylamine, 2-chloro-1,3,5-triazine-2,4,6-triamine,2,4-dichloro-1,3,5-triazine-2,4,6-triamine,2,4,6-trichloro-1,3,5-triazine-2,4,6-triamine,1-chloro-5,5-dimethylhydantoin, 1-bromo-5,5-dimethylhydantoin,1,3-dibromo-5,5-dimethylhydantoin1-chloro-3-bromo-5,5-dimethylhydantoin,1,3-dichloro-5,5-dimethylhydantoin,1-chloro-4,4,5,5-tetramethylimidazolidin-2-one,1,3-dichloro-4,4,5,5-tetramethylimidazolidin-2-one,1-chloro-2,2,5,5-tetramethylimidazolidin-4-one,1,3-dichloro-2,2,5,5-tetramethylimidazolidin-4-one,1,3-dichloro-s-triazine-2,4,6-trione, trichloroisocyanuric acid,potassium dichloroisocyanurate, sodium dichloroisocyanurate, potassiumdibromoisocyanurate, sodium dibromoisocyanurate, mono tohexachloromelamine, mono to hexabromomelamine,3-chloro-4,4-dimethyl-2-oxazolidinone, N-chlorosuccinimide,1-chloropyrrolidine-2,5-dione,1,3-dichlorotetrahydroquinazoline-2,4-dione,1,4-dichloro-2,2,5,5-tetrasubstituted-piperazine-3,6-diones,N-chloro-2,2,6,6-tetramethylpiperidine,N-chloro-4-amino-2,2,6,6-tetramethylpiperidine, polymer-boundN-chloro-N-sodiobenzenesulfonamidates, chlorinated polyacrylamide,brominated polyacrylamide, chlorinated poly(methacrylamide), brominatedpoly(methacrylamide), poly(N-chloro-2,2,6,6-tetramethyl-4-piperidinylacrylate), poly(N-chloro-hydantoin-methyl-p-styrene) emulsion,1-chloro-3-bromoalkyltrimethylammonium-4,4,5,5-tetramethylimidazolidin-2-one,1-bromo-3-bromoalkyltrimethylammonium-4,4,5,5-tetramethylimidazolidin-2-one,1-chloro-3-bromoalkyltrimethylammonium-2,2,5,5-tetramethylimidazolidin-4-one,1-bromo-3-bromoalkyltrimethylammonium-2,2,5,5-tetramethylimidazolidin-4-one,2-chloro-4-bromoalkyltrimethylammonium-1,3,5-triazine-2,4,6-triamine,2-bromo-4-bromoalkyltrimethylammonium-1,3,5-triazine-2,4,6-triamine,1-chloro-3-bromoalkyltrimethylammonium-5,5-dimethylhydantoin, and1-bromo-3-bromoalkyltrimethylammonium-5,5-dimethylhydantoin.

Some embodiments of this invention utilize an inert liquid carried whichdoes not react with halogen atoms in halogenated heterocyclicN-halamines. The inert liquid carrier can be a vegetable based ester ofthe structural formula: CH₃(CH₂)_(n)COOCH_(x)(CH₃)_(y), wherein nrepresents an integer which is within the range of 6 to 22, wherein xrepresents an integer which is within the range of 0 to 3, wherein yrepresents an integer which is within the range of 0 to 3, and whereinthe sum of x and y is 3. The inert liquid carrier will normally be ofthe structural formula: CH₃(CH₂)_(n)COOCH(CH₃)₂, wherein n represents aninteger which is within the range of 6 to 22. The integer n willtypically be within the range of 8 to 18 and is preferably within therange of 10 to 14. Isopropyl myristate which is of the structuralformula: CH₃(CH₂)₁₂COOCH(CH₃)₂ is an example of a highly preferred inertliquid carrier.

In one embodiment of this invention an odor resistant article is made byapplying a dispersion of a halogenated heterocyclic N-halamine in aninert liquid carrier to the surface of the article and allowing theinert liquid carrier to penetrate into the article, wherein the inertliquid carrier does not react with halogen atoms in the halogenatedheterocyclic N-halamine, and wherein the halogenated heterocyclicN-halamine becomes deposited on the surface of the article after theinert liquid carrier penetrates into the article. The articles which canbe made odor resistant in accordance with this invention are typicallycomprised of a solid material selected from the group consisting ofplastics, natural rubber, synthetic rubber, wood, porous inorganicmaterials, and fibers. In many cases the article will be comprised of asolid porous substrate. Some representative examples of porous inorganicmaterial that the article can be comprised of include aluminosilicate,kaolinite, montmorillonite-smectite, illite, and chlorite. Somerepresentative examples of fibers include cotton fibers, wool fibers,nylon fibers, polyester fibers, and aramid fibers. The article can alsobe comprised of a wide variety of solid materials, such as plastics,including polyolefins, polyamides, polyesters, polyurethanes,polycarbonates, and the like. For instance, the plastic can be lowdensity polyethylene, linear low density polyethylene, high densitypolyethylene, or polypropylene. In one mode of operation the halogenatedheterocyclic N-halamine provides odor resistance by deactivatingenzymes.

The inert liquid carrier can be applied to the surface of the articlebeing treated by using a wide variety of techniques. The optimumtechnique is dependent upon the nature of the article and its geometricstructure. In any case, the inert liquid carrier can typically besprayed onto the surface of the article. In some cases, it is convenientto apply the inert liquid carrier with a brush or to dip the articleinto a bath of the inert liquid carrier.

The halogenated heterocyclic N-halamine will normally be dispersed inthe inert liquid carrier in the form of particles which are in theparticle size range of about 0.01 μm to 20 μm. The particles of thehalogenated heterocyclic N-halamine will typically have a particle sizewhich is within the range of about 0.05 μm to 15 μm, and will moretypically be of particles size which is within the range of about 0.1 μmto 12 μm. The particles of the halogenated heterocyclic N-halamine willpreferably have a particle size which is within the range of about 0.1μm to 10 μm, and will more preferably be of particles size which iswithin the range of about 0.5 μm to 8 μm. In many cases the halogenatedheterocyclic N-halamine will be of a particle size which is within therange of about 1 μm to 6 μm, and will frequently be of particles sizewhich is within the range of about 3 μm to 5 μm.

The halogenated heterocyclic N-halamine will typically be dispersed inthe inert liquid carrier at a level which is within the range of about0.01 weight percent to about 50 weight percent. The halogenatedheterocyclic N-halamine will more typically be dispersed in the inertliquid carrier at a level which is within the range of about 0.05 weightpercent to about 25 weight percent. The halogenated heterocyclicN-halamine will normally be dispersed in the inert liquid carrier at alevel which is within the range of about 0.1 weight percent to about 10weight percent and will preferably be dispersed in the inert liquidcarrier at a level which is within the range of about 0.4 weight percentto about 5 weight percent. In many cases the halogenated heterocyclicN-halamine will be dispersed in the inert liquid carrier at a levelwhich is within the range of about 0.6 weight percent to about 2 weightpercent. The halogenated heterocyclic N-halamine will frequently bedispersed in the inert liquid carrier at a level which is within therange of about 0.8 weight percent to about 1.5 weight percent. It ispreferred for the halogenated heterocyclic N-halamine is insoluble inthe inert liquid carrier.

The method of this invention is highly useful for treating thermoplasticfilm to make it odor resistant. For instance, treating garbage bags inaccordance with the method of this invention to make them odor resistantis of particular commercial importance. In such a method a dispersion ofa halogenated heterocyclic N-halamine in an inert liquid carrier isapplied to the plastic film and the inert liquid carrier is allowed topenetrate into the plastic film leaving a coating of halogenatedheterocyclic N-halamine particles on the surface of the film. Thedispersion of the halogenated heterocyclic N-halamine in the inertliquid carrier is typically sprayed onto the surface of the film. As haspreviously been explained, it is important for the inert liquid carriernot to react with halogen atoms in the halogenated heterocyclicN-halamine. In any case, it is important for particles of thehalogenated heterocyclic N-halamine to become deposited on the surfaceof the plastic film after the inert liquid carrier penetrates into thefilm. In many cases the plastic film will be a polyolefin film, such asa polyethylene film. Low density polyethylene is useful in a widevariety of applications. As has been previously explained, in some casesthe halogenated heterocyclic N-halamine provides odor resistance bydeactivating enzymes.

In another embodiment of this invention other solid stable particulateoxidants, such as potassium monopersulfate and permanganates can besubstituted for N-halamines in certain applications and by the judiciousselection of liquid vehicles that are compatible with the deposition ofthe unreacted particulates on substrate surfaces. For example, a methodfor manufacturing a medium for purifying fluids can be made using such arationale. This method involves applying a dispersion of a micronizedmetal oxide in an inert liquid carrier to the surface of a substratehaving a high surface area and allowing the inert liquid carrier topenetrate into the substrate leaving the micronized metal oxide strandedon the surface of the substrate. In such applications, the micronizedmetal oxide will have a high affinity for sequestering contaminants,such toxic metals.

Another embodiment of this invention relates to a deodorizing solutionwhich is comprised of an organic liquid and a halogenated heterocyclicN-halamine, wherein the organic liquid does not react with halogen atomsin the halogenated heterocyclic N-halamine, and wherein the halogenatedheterocyclic N-halamine is soluble with the organic liquid. Thehalogenated heterocyclic N-halamine is normally a partially halogenatedhydantoin. In such deodorizing solutions the halogenated heterocyclicN-halamine will normally be present in the inert liquid carrier (theorganic liquid) at a level which is within the range of 0.1 weightpercent to about 5 weight percent, based upon the total weight of thedeodorizing solution. The halogenated heterocyclic N-halamine willtypically be present in the inert liquid carrier at a level which iswithin the range of 0.1 weight percent to about 4 weight percent, basedupon the total weight of the deodorizing solution and will moretypically be present at a level which is within the range of 0.2 weightpercent to about 3 weight percent, based upon the total weight of thedeodorizing solution. The halogenated heterocyclic N-halamine willpreferably be present in the inert liquid carrier at a level which iswithin the range of 0.5 weight percent to about 2.5 weight percent,based upon the total weight of the deodorizing solution and will morepreferably be present at a level which is within the range of 1 weightpercent to about 2 weight percent, based upon the total weight of thedeodorizing solution. A wide variety of substrates can be deodorized bysimply applying this deodorizing solution to the surface thereof.

In accordance with this invention, an aqueous medium can be deodorizedby dispensing an amount of the deodorizing solution which is sufficientto form an organic layer which extends substantially over the surface ofthe aqueous medium being deodorized. For example, a toilet bowl orurinal can be deodorized by dispensing the deodorizing solution into thewater in the toilet bowl or the urinal. The deodorizing solution istypically dispensed into the toilet bowl or the urinal upon beingflushing. For instance, the deodorizing solution can be dispensed intothe toilet bowl with the water that refills the toilet bowl after thetoilet is flushed. In deodorizing a toilet bowl it is preferable for thedeodorizing solution to be dispensed into the toilet bowl at a levelwhich is sufficient to coat the sides of the toilet bowl above the waterline and to provide an organic layer which extends substantially overthe surface of the water in the toilet bowl.

If the solid substrate is buoyant, as may be the case for certain formsof aluminosilicate (such as vermiculite), or organic particulates with alow demand for oxidants (such as sawdust derived from hardwoods, orcertain subsets of nut shells) or certain synthetic porous polymers(such as porous polypropylene), the microparticles applied to thesurface using the methods described above for zeolite can result in acoating, able to float on the surface of aqueous media, that confers onthe modified solid substrate a powerful capacity to contain andneutralize malodorants emanating from toilet waste or agriculturalmanure slurries. Such preparations can be of value in deodorizinglatrines, portable toilets, toilets in marine vessels, aircraft toilets,recreational vehicles (RVs), livestock manure lagoons, and the like. Inmany applications of this type the buoyant material is particularlyeffective because it is dispersed on the surface of the liquid beingdeodorized.

Still another embodiment of this invention relates to a method formanufacturing a medium for purifying fluids containing toxic compoundswhich comprises applying a dispersion of a halogenated heterocyclicN-halamine in an inert liquid carrier to the surface of a substratehaving a high surface area, such as a conventional air or liquid filter,and allowing the inert liquid carrier to penetrate into the substrate.It is important for the inert liquid carrier not to react with halogenatoms in the halogenated heterocyclic N-halamine. It is also importantfor the halogenated heterocyclic N-halamine to be capable of destroyingthe toxic compound, such as toxic gases including nerve gas or mustardgas, by oxidative action, and for the halogenated heterocyclicN-halamine to become deposited on the surface of the substrate after theinert liquid carrier penetrates into the substrate. The techniques ofthis invention can be used to deodorize hard surfaces, such countertops,which are comprised of a metal, a ceramic, tile, glass, masonry, wood,porcelain, stone, polymeric materials, and the like.

Air and water filters can be manufactured in accordance with thisinvention to deodorize air or water by treating the filtration mediumwith a dispersion of a halogenated heterocyclic N-halamine in an inertliquid carrier. For instance, the air filtration medium can be a HEPAfilter. The filtration material can be comprised of a multitude ofnon-woven polyester fibers which are bound together with anethylene-vinyl chloride copolymer binder into the form of a sheet. Thepolyester used in making the non-abrasive fabric is typicallypolyethylene terephthalate or polyethylene naphthalate having anintrinsic viscosity which is within the range of 0.45 dl/g to about 0.85dl/g. The polyester will more typically have an intrinsic viscositywhich is within the range of 0.50 dl/g to about 0.75 dl/g and willnormally have an intrinsic viscosity which is within the range of 0.50dl/g to about 0.70 dl/g. In most cases the polyester will have anintrinsic viscosity which is within the range of 0.55 dl/g to about 0.65dl/g. It is normally preferred to utilize a polyester having anintrinsic viscosity which is within the range of 0.60 dl/g to about 0.64dl/g. Polyethylene terephthalate (PET) resins that are useful in thepractice of this invention are commercially available from Gruppo Mossi& Ghisolfi and Eastman Chemical). For instance, Cleartuf® P60 PET resinwhich has an intrinsic viscosity of 0.58 dl/gram, an acetaldehydecontent of ≤80 mg/kg, and a melting point of 250° C. can be used inmanufacturing the non-woven fabric. Cleartuf® P76 PET resin which has anintrinsic viscosity of 0.74 dl/gram, an acetaldehyde content of 1.0 ppm,and a melting point of 250° C. can optionally be used in manufacturingthe non-woven fabric.

The fabric used for filtration is typically comprised of a multitude ofnon-woven polyester fibers which are bound together in the form of asheet with an ethylene-vinyl chloride copolymer binder. The polyesterfibers in the non-woven fabric typically have a diameter which is withinthe range of about 10 micrometers to about 50 micrometers and more havea diameter which is within the range of about 15 micrometers to about 40micrometers. In most cases the polyester fibers have a diameter which iswithin the range of about 20 micrometers to about 30 micrometers. It isnormally preferred for the polyester fibers have a diameter which iswithin the range of about 22 micrometers to about 27 micrometers.

The non-woven fabric of the filtration material will typically have adensity which is within the range of about 0.01 grams/cc to about 0.40grams/cc and will more typically have a density which is within therange of about 0.02 grams/cc to about 0.30 grams/cc. In most cases thefiltration medium will have a density which is within the range of about0.03 grams/cc to about 0.20 grams/cc. It is normally preferred for thefiltration medium (fabric) to have a density which is within the rangeof about 0.04 grams/cc to about 0.15 grams/cc. It is generally morepreferred for the fabric to have a density that is within the range ofabout 0.05 grams/cc to about 0.10 grams/cc. It is normally mostpreferred for the fabric to have a density that is within the range ofabout 0.06 grams/cc to about 0.08 grams/cc.

The ethylene-vinyl chloride polymer (EVC) binder utilized inmanufacturing the filtration medium fabric can optionally be crosslinkedwith an external crosslinker, such as melamine or a urea formaldehyderesin to achieve improved wet tensile properties. The use ofethylene-vinyl chloride polymer emulsions as binders for nonwovenfabrics is described in U.S. Pat. No. 7,247,568. The teachings of U.S.Pat. No. 7,247,586 are incorporated herein by reference for the purposeof teachings the types of ethylene-vinyl chloride polymer emulsions thatcan be used in manufacturing filtration material and a for the purposeof teaching methods for manufacturing fabric filtration materials withsuch EVC binders.

This invention is illustrated by the following examples which are merelyfor the purpose of illustration and are not to be regarded as limitingthe scope of the invention or the manner in which it can be practiced.Unless specifically indicated otherwise, parts and percentages are givenby weight.

Example 1

The objective of this experiment was to demonstrate that when naturalzeolite granules are exposed to a dispersion of particles ofapproximately 5 microns the absorption of the liquid vehicle into theporous zeolite leaves the micro particles exposed on the surface of thealuminosilicate granules. Latex spheres having an average diameter of 5microns were purchased from Sigma Aldrich Inc, St. Louis, Mo., andsuspended as a dispersion in water, since they are not soluble in thismedium. Then, clinoptilolite aluminosilicate zeolite granules (14×40mesh) were mixed with the dispersion until the fluid had soaked into thesubstrate. Samples were then vacuum dried and coated for scanningelectron microscopy (SEM). Images of the surface of the zeolite showed acoating of 5 micron particles present in the crevices and voids of thecoarsely irregular outer surface. This SEM image is shown in FIG. 1.Latex spheres were used because their uniform shape made them readilyidentifiable against the irregular background micro-topography of thezeolite. Micronized particles of the N halamine were irregular in shapeand not clearly distinguishable from the background by SEM. However,when the surface was scanned using Energy Dispersive X-Ray Spectroscopy(EDS) a clear signal for surface chlorine was detected at 2.3 keVagainst the aluminosilicate background in SEM. The EDS line scan of thesurface of the zeolite granules exposed to a dispersion of N-halaminemicronized particles (5 microns average diameter) suspended in an inertorganic vehicle after absorption of the vehicle into the porous matrixto the zeolite is shown in FIG. 2. N-halamine particles on the surfacecontain chlorine, clearly identifiable against the background ofaluminosilicate elemental constituents detected by this technique. Thisexperiment illustrates the principle of coating micronized particlesonto porous substrates using a dispersion of the active particles.

Example 2

This experiment was performed to illustrate the method of manufacturingan odor resistant animal litter. In the procedure used twenty grams (20g.) of micronized 1-chloro-5,5-dimethylhydantoin and 5 grams micronized1-chloro-2,2,5,5-tetramethylimidazolidin-4-one with size around 5 umwere dispersed into 40 grams of isopropyl myristate, and agitated for 30minutes. The resulting mixture was a white and stable dispersion. Thedispersion was sprayed onto 2 kg of Montmillorite zeolite granules witha spray painting gun. The treated zeolites did not show obvious visiblechanges. The coating can be expected to significantly reduce the finedust particles in litter. The treated zeolite was found to react with a1% solution of potassium iodide to produce a deep brown color,indicative of the presence of oxidant power on the surface of theN-halamine coated granules. This reactivity on contact with potassiumiodide persisted unchanged for many months of storage at roomtemperature.

Example 3

The purpose of this experiment was to illustrate the means ofcharacterizing the coated granular medium by titration of the activechlorine contents. In the procedure used coated zeolite Cl contents weredetermined by iodometric titration. Approximately one half gram ofcoated zeolite granules was ground into fine powder, and treated with 1g of potassium iodide (KI) in 100 mL of deionized water (the solutioncontained 0.05% (v/v) of TX-100). The mixture was stirred constantly atroom temperature for 1 hour. The molecular iodine formed (I₂) wastitrated with standardized aqueous sodium thiosulfate solution. Uncoatedzeolite granules were tested under the same conditions to serve ascontrols. The available active chlorine content on the zeolites wascalculated according to equation (1):

$\begin{matrix}{{{Cl}\mspace{14mu}\%} = {\frac{35.5}{2} \times \frac{\left( {V_{S} - V_{0}} \right) \times C_{{Na}_{2}S_{2}O_{3}}}{W_{S}} \times 100}} & (1)\end{matrix}$where V_(S), V₀, C_(Na2S2O3) and W_(S) were the volumes (mL) of sodiumthiosulfate solutions consumed in the titration of the coated anduncoated samples, the concentration (moles/L) of the standardized sodiumthiosulfate solution, and the weight of the chlorinated sample (mgram),respectively. By adjusting the N-halamine concentration in the treatmentprocess, it was determined that a series of coated zeolites could beprepared with active chlorine contents of 654, 1143, and 2057 ppm,respectively.

Example 4

The purpose of this experiment was to illustrate the method ofmanufacturing an odor resistant plastic film coating. Twenty grams (20g) of micronized 1-chloro-5,5-dimethylhydantoin and 2 grams ofmicronized 1-chloro-2,2,5,5-tetramethylimidazolidin-4-one (averageparticle size approximately 5 um) were dispersed into 20 grams ofisopropyl myristate, and agitated for 30 minutes. The resulting mixturewas a white and stable dispersion. For each LDPE plastic bag serving assubstrate for the coating procedure, 0.5 gram of the resultingdispersion was applied onto the inner surface with a fabric wiper. Thetreated plastic bag did not show obvious visible changes, other than avery slight oily sheen that disappears after several days of storage.Chlorine titration of the active coated plastic showed a content of 150mgram per square meter.

Example 5

The purpose of this experiment was to illustrate the method ofmanufacturing an odor resistant article. Ten grams (10 g) of micronized1,3-dichloro-5,5-dimethylhydantoin and 2 grams micronize1-chloro-2,2,5,5-tetramethylimidazolidin-4-one with an average size ofabout 5 um were dispersed into 30 grams of vegetable-based ester,agitated for 30 min; the resulting mixture was a white and stabledispersion. The resulting dispersion was sprayed onto 2 kg hydratedcalcium silicate granules with a sprayer bottle. The treated calciumsilicate granules did not show obvious changes. The coating can beexpected to significantly reduce the fine dust particles from the litterduring normal use. Chlorine titration indicated the presence of 576 ppmactive chlorine.

Example 6

The purpose of this experiment was to demonstrate the microparticles ofN-halamine coated onto zeolite granules could have odor control effectson offensive malodorants when in direct contact with these substances.This was accomplished by exposing 3-mercapto-3 methyl 1 butanol (3M3 MB)to uncoated zeolite granules as a negative control or to zeolite exposedto a dispersion of the micronized N halamine. Aliquots (1.5 g) of eachsample were added to 5 mL of 1 mM 3M3 MB in 50 mM MES buffer containing150 mM KCl at pH 6.2. The suspensions were mixed well before serialsampling of the supernatants obtained at each time point by centrifugingthe mixtures at 8000 rpm for 20 seconds. Supernatants (50 μL) were addedto cuvettes containing 50 μL of 20 mM DTNB solution and 900 μL of 50 mMMES buffer at pH 6.8. The absorbance of TNB⁻ was measured at 412 nm. Acalibration curve in 50 mM MES buffer at pH 6.8 had been prepared givingan extinction coefficient of 13986 M⁻¹cm⁻¹.

The results showed that whereas in the negative control there was only a0.5% reduction in the amount of thiol detected spectrophotometricallyafter exposure, the reduction after contact with the N-halamine coatedgranules was 99.5%. These data indicate that the micronized particlecoated medium may exert powerful malodor control by direct chemicaldegradative effects on targets such as thiols.

Example 7

In this experiment the effect of contact of a malodorant (3M3 MB) withmicronized coated zeolite granules was measured in the headspace abovethe reaction mixtures using GC MS procedures. A solution (2 mL)containing 100 ppm 3M3 MB and 200 ppm β-mercaptoethanol in 50 mMphosphate buffer pH 7.0 was added to 500 mg of each litter in a 10 mLSupelco glass headspace vial. Headspace analysis was done using aSupelco SPME PDMS/Carboxen 75 μm fiber and an adsorption time of 10minutes. This fiber was chosen based on the molecular weight of thecompounds used. Before use and in between each type of litter, a fiberblank was performed in order to clear the fiber of potential residuesfrom earlier runs. An Agilent 6850 series GC with a 0.75 mm×6.35×78.5inlet liner was used. The oven settings were programmed to 40° C. for 5minutes, then ramping up to 125° C. at 8.5° C./minute for a total of 15minutes. The column had a flow rate of 1.2 mL/meter and the detectortemperature was set at 300° C. The inlet temperature was set to 250° C.with the pressure at 9.14 psi. The mass spectrophotometer used was anAgilent 5973 Network Mass Selective Detector. The headspace was analyzedfour times for each of the negative control and the coated zeolitesamples. The ratio of the 3M3 MB to β-mercaptoethanol peak areas, andthe ratios of the oxidized 3M3 MB to β-mercaptoethanol peak areas wereaveraged, and a standard deviation calculated for each test condition.

The ration of the thiol to mercaptoethanol standard for the negativecontrol was approximately 4.5:1. There was no thiol detectable in theheadspace above the mixture of 3M3 MB with the N-halamine-coated zeolitegranules. These results indicate that the direct degradative effect ofthe coated zeolite can lead to rapid and complete elimination ofcommonplace malodorants such as sulfanyl butanol. Similar findings wereobserved for a related sulfanyl hexanol compound. Since sulfurcontaining inorganic (e.g., H₂S) and organic compounds can be toxicand/or irritants this result may be taken also to mean that the mediummay be useful in detoxification of contaminated fluids or flows of air.

Example 8

In this experiment the effectiveness of micronized N-halamine coatedzeolite granules was tested in a system that was evaluated by a panel ofhuman subjects exposed to the headspace above the reaction mixtures.Sensory evaluation of the efficacy versus 3M3 MB was determined bycomparing uncoated zeolite as a negative control with the coatedmaterial. 125 mL of the two test samples plus the control zeolites in1.25 L glass vessels were assessed for their capacity to affect theheadspace scores assigned by a ten-member panel after the addition of 1mL of 1% w/w of 3M3 MB. Vessels were securely covered, and allowed toequilibrate for four hours prior to scoring. Beakers were coded withrandom numbers, and presented to judges in irregular order. Judgesparticipated in a training session to clearly understand the sensoryattributes to be scored, and to practice the evaluation protocol. Eachjudge scored the test headspaces as either acceptable (0) or offensive(10), or at some level in between.

All judges found the thiol odor in the negative control zeolite to beoffensive. Nine scored the sample incubated with the N-halamine coatedpositive control as acceptable. No intermediate scores were assigned byany of the judges. These results demonstrate the utility of the coatedmedium in affecting the mitigation of malodor perceived by humansubjects exposed to a sulfurous organic compound.

Example 9

The purpose of this experiment was to demonstrate the odor controleffectiveness of micronized N-halamine particle-coated zeolite granuleswhen used as a top dressing or sprinkle on the surface of conventionalcat litter challenged with a volatile urine malodorant. In the procedureused two grams (2 g) of commercial cat litter granules (Catsan by MarsInc, or Double Duty by Church and Dwight Inc.) or 2 gm of uncoatedzeolite granules as control were placed in 10 mL glass vials. To thesesamples were added 1 ml aliquots of an aqueous solution containing 100ppm 3-mercapto-3-methylbutan-1-ol as a urine-derived malodorant. Testflasks were treated with either a top dressing of 100 mg of Arm andHammer Double Duty odor control sprinkles or 100 mgs of micronizedN-halamine-coated zeolite particles from OxiScience LLC, Redmond Wash.

Headspace analysis was done using GC/MS by absorbing a gas sample onto aSupelco SPME PDMS/Carboxen 75 um fiber, placed in the headspace for 10minutes. The fibers were then placed in an Agilent 6850 series GC with a0.75 mm×6.35×78.5 inlet liner. The oven settings were programmed to 40°C. for 5 minutes, then ramping up to 125° C. at 8.5° C./minute for atotal of 15 minutes. The column had a flow rate of 1.2 mL/meter and thedetector temperature was set at 300° C. The inlet temperature was set to250° C. with the pressure at 9.14 psi. The mass spectrophotometer usedwas an Agilent 5973 Network Mass Selective Detector. Collected molecularweight 45-190 g/mol. Each experimental and control vial sample was setup in triplicate.

No detectable thiol was present in the headspace of the vials that weresprinkled with the N-halamine coated zeolite. The vials containing catlitter had 10.5, 11.2 and 9.4 ngm of thiol for the Arm and Hammer DoubleDuty, Catsan and Zeolite (control), respectively. Sprinkling with Armand Hammer Odor Control litter top dressing had no effect on themalodorant levels.

This result shows that N-halamine coated zeolite is effective atcontrolling cat urine odors caused by volatile thiols, even when used asa top dressing on conventional litter granules that are themselvesineffective in affecting the malodorant.

Example 10

The purpose of this experiment was to demonstrate the antibacterialactivity of zeolite granules coated with micronized N halamineparticles. This was determined in a contact test using a urease positivestrain of Proteus vulgaris bacteria. Bacterial suspensions in brothculture were washed in sterile phosphate buffer (PBS) solution,sedimented by centrifugation, and resuspended in PBS at 108 cfu/ml forthe challenge. One milliliter was added to 5 g of the test sample of Nhalamine coated zeolite (in triplicate), and to triplicates of negative(uncoated) zeolite controls. After measured contact times, 20 mL 0.03weight percent sodium thiosulfate aqueous solution was added to eachsample so as to quench the active chlorine in the N halamine particlesin the positive controls. The mixtures were vortexed for 1 minute, andsonicated for 5 minutes, before plating 10 μl aliquots from serialdilutions onto agar plates for colony counts after incubation at 37° C.for 24 hours.

Exposure to the N halamine-coated zeolite produced a log reduction value(LRV) of 6 (i.e., 99.9999%) at all time points tested, compared tocontrol. This result shows the utility of coated zeolite in inhibitingthe growth of an odor-causing microbe (P. vulgaris), as a potentialmechanism in the efficacy of this medium in controlling development ofmalodors.

Example 11

In this experiment the efficacy of micronized particle N-halamine coatedzeolite on inhibition of a common odor-generating enzyme was determined.A solution containing Canavalia ensiformis Urease (10 U/mL), 200 mMphosphate buffer, pH 7.0 was incubated with 100 mg of the coated zeoliteand control uncoated medium at room temperature. After 5 minutes, thesamples were centrifuged for 60 seconds at 10,000 rpm, and thesupernatant was removed and urea (15 mM) was added. 100 μL of thissolution was assayed following the Sigma Aldrich (St. Louis, Mo.)Ammonia Assay Kit protocol (AA0100). Briefly, a 100 μL aliquot was addedto the Ammonia Assay Reagent and incubated for five minutes. Then, 10 μLof L-glutamate dehydrogenase was added and the initial absorbance at 340nm was recorded. The final absorbance was measured after 5 minutes.

Jack Bean Urease activity was used as an indicator of inhibitoryeffects. Urease activity alone produced 297.3 μg/mL of NH3, while thenegative zeolite control reduced the activity to 158.5 μg/mL. A largedecrease in Urease activity occurred with the N-halamine-coated zeolitesample with only 4.5 mcg of ammonia being generated after contact. Theresult with this medium indicates that the coated granules may exertuseful effects on malodor control through inhibition of microbialenzymes such as ureases that generate odor from substrates such as urea,and can be expected to inhibit other enzymes such as lyases, forexample, that produce malodorous volatile sulfurous compounds frommacromolecules and peptides that contain sulfur residues.

Example 12

The purpose of this experiment was to demonstrate that N-halamine coatedzeolite granules, prepared by deposition of micronized particles ontothe surface of the aluminosilicate substrate, could serve as aneffective malodorant removal medium in an air filtration device. Thepleated nonwoven membrane filter was removed from a room air filter(Beiang Corp, Beijing, China, Model A8) and replaced with a cassette8×12×¾ inches filled with ˜1 kilogram of N halamine coated zeolitegranules. Then, a 10×10 ft enclosed space with limited air exchange wasused to create a malodorous atmosphere by spreading 100 grams of anorganic fertilizer on the floor of the room overnight. At this point apanel of six people were admitted singly into the room and each allowedto score the degree of malodor. The air filter fitted with the coatedzeolite was then installed in the room for 90 minutes, drawing airthrough the filter at the rate of 800 cubic meters per hour (m³/hour).Then, the observers were asked to return and score the atmospherepost-air filtration. All observers reported a high degree of removal ofthe offensive odor.

This result illustrates the usefulness of a N-halamine coated medium asa component of an air filtration treatment train in removing complexmixed offensive odors in a confined air space. This result alsoillustrates the usefulness of a N-halamine coated medium as a componentof an air filtration treatment train in removing complex mixed offensiveodors in a confined air space.

Example 13

The purpose of this experiment was to demonstrate the efficacy of theN-halamine coated zeolite medium as a component of an air filtrationdevice used to reduce the odor of marijuana plants in a grow operationin Carnation, Wash. In an administration area of 600 sq ft adjacent to a5000 sq ft grow facility the odor of the marijuana was noticeable to anobserver immediately on entry. The air filtration device used in Example12 was set up in the room with an 8×12×¾ inch cassette containing ˜1kilogram of N-halamine coated zeolite granules. The device was run atmaximum flow for 30 minutes. After that time the observer re-entered thespace and determined that the distinct odor of the plants haddisappeared altogether. This result confirms the utility of the coatedzeolite as a means of a specific nuisance odor control (from marijuana,and suspected to be largely terpenes) in a confined space.

Example 14

This experiment was done to illustrate the ammonia control performanceof microparticulate N halamine-coated zeolites in comparison to anuncoated commercial horse stall refresher zeolite product (PDZ). In thisexperiment odor control properties of animal litters were determinedusing an ammonia test protocol by exposing them to diluted ammoniasolution (0.6 weight percent). One hundred and twenty five mL of animallitter was placed into a 1.25 L glass vessel; each vessel was sealedwith plastic film. On a daily basis, 1 mL of the ammonia solution wasapplied onto the animal litter to simulate daily deposits of urine by ananimal using the stall bedding product or the coated zeolite medium.After applying the ammonia solution for 5 minutes the ammonia content inthe headspace of each carrier vessel was determined using an NH₃ testmeter. Tests were conducted daily for 3 days without replacement of thelitter media.

It was observed (FIG. 3) that the N halamine coated zeolite granulesprovided superior and faster odor control than PDZ horse stall refresherproduct. Owing to the noticeable odor abatement and the relatively lowchlorine content of the coated zeolites, the active chlorine componentis appeared to be primarily functioning as a rapid odorneutralizer/degrader rather than as an odor absorbent. The level ofheadspace ammonia content detected after 1 day, 2 days, and 3 days isshown below in Table 1.

TABLE 1 Headspace Ammonia Contest Detected 1 Day 2 Days 3 Days TreatedZeolite 0 ppm  0 ppm  3 ppm PDZ Horse Stall Refresher 8 ppm 17 ppm 24ppm

FIG. 3 is a bar graph that provides this data. The ammonia contentsshown were detected as immediate (5 minute) headspace ammonia contentafter daily litter applications of ammonia equivalent to an animal'surine deposits, assuming all the urinary urea is microbially convertedto ammonia each day.

Example 15

This example illustrates the preparation of a toilet deodorizing spray.One gram of 1,3-dichloro-5,5-dimethylhydantoin and 0.1 gram micronized1,3-dichloro-2,2,5,5-tetramethylimidazolidin-4-one with were dispersedin 99 grams of vegetable-based ester using magnetic agitation overnightat room temperature. The resulting liquid was clear and withoutnoticeable odor. Chlorine titration indicated the presence of 1875 ppmactive chlorine.

Example 16

This example illustrates the preparation of toilet deodorizing spray.One gram of 1-chloro-5,5-dimethylhydantoin and 0.2 gram1-chloro-2,2,5,5-tetramethylimidazolidin-4-one were dispersed in 30grams isopropyl myristate using magnetic agitation overnight at roomtemperature. The resulting liquid was clear and without noticeable odor.Chlorine titration indicated the presence of 489 ppm active chlorine.

Example 17

This experiment was performed to illustrate the odor control performancecomparison of a toilet-deodorizing formulation applied as a spraycompared with the performance of a commercial product (Poo-pourri“Before-you-go” toilet spray composed of essential oils). Hydrogensulfide (H₂S) was chosen as the surrogate for malodorous volatilecompounds emitted by human waste.

The odor control properties of the toilet spray formulation weredetermined by its effects on H₂S solution (lab made) utilizing ahydrogen sulfide (H₂S) test protocol: In the procedure used one hundred100 mL of water was placed into a 1.25 L glass vessel and each vesselwas then sealed with plastic film. A negative control vessel received0.5 mL water as negative control. One half mL of the toilet sprayformulation prepared as in example 6, served as test sample, and 0.5 mLof Poo-pourri toilet spray served as positive control. Two mL (2 ml) ofthe H₂S solution was injected into the water layer in each sealedvessel. After applying the H₂S solution for 1 min, the H₂S content inthe headspace of each carrier vessel was determined using the testmeter. The results of this experiment are provided in Table 2 and areshown in bar graph form in FIG. 4. The H₂S levels reported weredetermined immediately (within 1 minute) after applying the H₂S solutioninto the water.

Headspace Hydrogen Sulfide (H₂S) Content Water (Negative Control) 13ppm  Poopourri (Positive Control) 8 ppm Experimental Sample 2 ppm

It was observed that the N-halamine-coated test sample provided superiorand faster odor control than the positive control (Poo-pourri). Owing tothe marked effect on H₂S odor abatement and the relatively small amountof active chlorine component in the sample formula, it appeared that theactive chlorine was primarily functioning as a rapid H₂Sneutralizing/degrading agent rather than as an absorptive agent.

Example 18

The objective of this experiment was to demonstrate that microparticlesof functional metal oxides could also be displayed on the surface ofzeolite substrate after exposure to dispersions of the particles. Inthis case suspensions of insoluble micronized cerium oxide particleshaving an average diameter of 3 microns (Advanced Abrasives Inc) wereprepared in water. Exposure of 14×40 mesh zeolite granules to a slurryof CeO led to absorption of the liquid vehicle. Coated granules werethen dried and prepared for SEM, and scanning using EDS. These imagesshowed that crystalline microparticles of about 3 microns in size wereevenly distributed over the highly irregular surface of thealuminosilicate substrate. Approximately 20% of the elementalcomposition in a surface linear scan was found to be attributable tooxides of cerium, with signals predominantly over the 4.3-6.3 key range.

This result indicates that surface coating of zeolite with metal oxidepreparations known to be functional in a variety of absorptiveinteractions with water contaminants is achievable with this method.Cerium oxides are known to be highly effective in their interaction withligands such as fluoride and other toxic contaminants in aqueous mediumor in air, especially when Ce is present with other metal oxides such asaluminum and iron.

Variations in the present invention are possible in light of thedescription of it provided herein. While certain representativeembodiments and details have been shown for the purpose of illustratingthe subject invention, it will be apparent to those skilled in this artthat various changes and modifications can be made therein withoutdeparting from the scope of the subject invention. It is, therefore, tobe understood that changes can be made in the particular embodimentsdescribed which will be within the full intended scope of the inventionas defined by the following appended claims.

What is claimed is:
 1. A highly efficient air filter which is comprisedof an air filtration medium which has been treated with a dispersion ofhalogenated heterocyclic N-halamine in an inert liquid carrier whereinthe halogenated heterocyclic n-halamine is a partially halogenatedhydantoin of the structural formula:

where X₁ and X₂ independently represent hydrogen atoms or halogen atomsR₁ and R₂ independently represent linear or branched alkyl groupscontaining from 1 to about 10 carbon atoms.
 2. The highly efficient airfilter of claim 1 wherein the halogenated heterocyclic N-halamine ismonochloro-5,5-dimethyl hydantoin.
 3. The highly efficient air filter ofclaim 1 wherein the halogenated heterocyclic N-halamine is insoluble inthe inert liquid carrier.
 4. The highly efficient air filter of claim 1wherein the inert liquid carrier is a vegetable based ester.
 5. Thehighly efficient air filter of claim 1 wherein the inert liquid carrieris isopropyl myristate.
 6. The air filter of claim 5 wherein thefiltration medium is comprised of a multitude of non-woven polyesterfibers which are bound together with an ethylene-vinyl chloridecopolymer binder.
 7. The air filter of claim 6 wherein the polyesterfibers in the non-woven fabric have a diameter which is within the rangeof about 10 micrometers to about 50 micrometers.
 8. The highly efficientair filter of claim 1 wherein the treated air filtration medium iscontained within a nonwoven air filtration medium.
 9. The highlyefficient air filter of claim 1 wherein the air filtration medium is analuminosilicate or a hydrated aluminosilicate which is selected from thegroup consisting of bentonite, montmorillonite, pumice, and zeolite. 10.The air filter of claim 6 wherein the non-woven polyester fibers arepolyethylene terephthalate fibers having an intrinsic viscosity which iswithin the range of 0.45 dl/g to 0.85 dl/g.
 11. The air filter of claim10 wherein the air filtration medium has a density which is within therange of 0.01 g/cc to 0.4 g/cc.